10.6084/m9.figshare.5259712.v1 Anne E. Winters Anne E. Winters Naomi F. Green Naomi F. Green Nerida G. Wilson Nerida G. Wilson Martin J. How Martin J. How Mary J. Garson Mary J. Garson N. Justin Marshall N. Justin Marshall Karen L. Cheney Karen L. Cheney Figures S1 - S7 from Stabilizing selection on individual pattern elements of aposematic signals The Royal Society 2017 colour pattern warning signals genetic differentiation marine molluscs 2017-07-31 08:14:27 Journal contribution https://rs.figshare.com/articles/journal_contribution/Figures_S1_-_S7_from_Stabilizing_selection_on_individual_pattern_elements_of_aposematic_signals/5259712 Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, <i>Goniobranchus splendidus</i>, which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, <i>Rhinecanthus aculeatus</i>, used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.